基于生物质谱技术高通量鉴定蛋白糖基化修饰的新方法

Glycosylation is very important, but there is no high throughput way to observe all the structure changes happened at sugar chain at omics level. If the technique problem has been overcome, it will be great helpful for biologists to re-understand the role of sugar and its structure in organisms. We utilized common experimental methods in glycomics and combined with all kinds of characteristics in mass spectrometry instrument, developed a new high-throughput method to scan all the glycopeptides in real sample, named GRIP. GRIP is able to assist non-professional researcher quickly, accurately identify all the glycopeptides from a large number of mass spectra, and provide the supporting evidence including peptide sequences, modification sites, and glycan compositions. Though the accuracy of GRIP has been strictly validated in the standard glycoprotein and human serum sample, it needs improvement. Through this project, we will optimize GRIP, make it possible for identification of N-glycoproteins or O-glycoproteins in multiple species/organs by different types of mass spectrometry instrument. Meanwhile, we will apply GRIP to the real complex biological samples, including mouse liver tissue and human liver cancer metastasis cell lines, reveal all the structure changes happened in glycan. All the results will be verified through special experiments.

蛋白质糖基化修饰的重要性不言而喻，但一直缺乏一种高通量技术可在组学水平上观测生物体内糖链结构的变化，如果这一领域得到攻克，可以很大程度的帮助生物学家重新认识糖及其结构在生物体中的作用。我们利用糖组学中常用的实验方法并结合质谱仪的各类特性，初步建立了一套N-糖肽组成的高通量鉴定方法（GRIP），能够辅助实验人员快速准确地从海量谱图中识别糖肽，给出肽段序列、修饰位点，糖链组成等支持证据。标准糖蛋白以及人类血清样品的预实验表明GRIP有一定的准确度，但仍需不断完善。通过本项目，一方面我们将优化、拓展GRIP软件功能，使其能够利用不同类型的质谱来鉴定多物种、多组织器官中表达的N-糖蛋白与O-糖蛋白，另一方面将GRIP方法运用到实际复杂样品中，鉴定小鼠肝脏组织中糖蛋白及糖链结构的种类，深入挖掘肝癌转移过程中参与的糖蛋白及其糖型结构的变化，并设计实验验证。

蛋白质糖基化修饰的重要性不言而喻，但一直缺乏一种高通量技术可在组学水平上观测生物体内糖链结构的变化，如果这一领域得到攻克，可以很大程度的帮助生物学家重新认识糖及其结构在生物体中的作用。我们基于现有的质谱技术，开发了一些糖蛋白质组搜索引擎和实验体系。在研究的4个阶段中，分别建立了GRIP、pGlyco和pGlyco+这三个软件方法和实验体系，外加一个糖链拓扑结构库pGlycoDB。而pGlyco+最有希望成为国内最主流的糖蛋白鉴定方法。同时，我们在人类血清样品、小鼠的各个脏器中都得到了完美的测试结果。